GBCTN-350 CNC 6 Axis Hobbing Machine
The GBCTN-350 CNC 6 Axis Hobbing Machine processes large gear blanks up to Φ350 mm and module M8, delivering the high torque and rigidity demanded by heavy industrial, offshore, and energy-sector gear manufacturers. A Φ260-300 mm direct-drive table generating 900-1000 Nm torque and FANUC 0i-MF Plus control underpin its large-diameter ultra-precision machining capability.
GBCTN-350 CNC 6 Axis Hobbing Machine — Large-Diameter Precision for Demanding Industrial Gears
The GBCTN-350 is the large-bore variant of the GBCTN-200/350 series, configured for manufacturers who regularly process gear blanks in the Φ200-350 mm diameter band at modules up to M8. The Φ260 mm standard table (Φ300 mm optional) accepts large chuck fixtures for ring-gear and annulus-type blanks, while the 35 KVA power supply and S1=35.8 Nm hob-spindle torque are matched precisely to M8 alloy-steel stock removal. For manufacturers producing large cement-mill drive pinions, heavy marine reduction-gear sets, or M8 gearbox components, the GBCTN-350 is the natural choice. Visit the GBC CNC Hobbing Machine overview page to see how this model fits within our full capacity range.
Large-Table Design & High-Torque Drive System
At the heart of the GBCTN-350 is its oversized C-axis table — standard at Φ260 mm, expandable to Φ300 mm on order — driven by a direct-torque motor rated at 900 Nm (1000 Nm optional). This eliminates the torsional compliance found in worm-drive tables, giving the FANUC interpolator direct authority over workpiece angular position at all feed rates. The 350 mm (340-690 mm) U-axis hydraulic tailstock travel generously accommodates both short-disc and long-shaft workpieces. A wide Z-column base ensures the machine handles eccentric loading from asymmetric fixtures common in job-shop environments machining custom large-module gear blanks.
❖ Key Features
️ High-Rigidity Heavy-Machining Bed
Shared-architecture casting adapted for larger table clearances; hardened-steel guideway inserts on all linear axes protect against wear at high chip loads.
Stable Adjustable Rolling Hob-Head Spindle
BT#40 taper spindle nose supports Φ150 mm x 220 mm hobs; field-adjustable preload bearings maintain <3 um runout throughout hob-life cycle.
High-Torque Large-Diameter Ultra-Precision Machining
Φ260/300 mm table with 1000 Nm direct-drive torque enables deep-cut large-module ring-gear hobbing that eliminates pre-roughing on a separate lathe.
High-Speed Direct-Drive Rotary Table
Max. 200/300 rpm table rotation for high-speed semi-finishing passes; direct-drive eliminates angular-position error accumulation of worm-table designs.
Stainless Mirror Chip Trough
Polished stainless inner skin with steep-angled drainage directs large M8 chips directly to the conveyor, reducing manual chip clearance intervals.
️ FANUC 0i-MF Plus & 35 KVA Supply
Nano-interpolation and synchronous electronic gearbox ensure sub-arc-minute synchronisation between hob spindle and table — critical for M8 gear pitch accuracy.
Primary Application Markets
️ Heavy Construction Machinery
Swing-bearing internal gears, track-drive final-drive gears, and dozer final-drive pinions where M6-M8 module and high case-depth are standard.
⛏️ Mining & Bulk Handling
Conveyor-drive sprocket gears, crusher-drive pinions, and mill-drive intermediate gears where shock resistance and surface hardness are paramount.
⚙️ Large Speed Reducer OEM
Input and intermediate stage gears for multi-stage industrial reducers rated above 100 kW, typically requiring certified M6-M8 tooth geometry.
Job Shops & MRO Facilities
Repair and reverse-engineering of large-module replacement gears for obsolete gearboxes — the GBCTN-350's flexibility across multiple module sizes makes it ideal.
️ Offshore & Subsea Equipment
Pressure-rated gearbox components for subsea BOPs, wellhead actuators, and offshore crane slewing rings demanding DIN 5 precision.
Technical Specifications
| Parameter | GBCTN-350 Specification |
|---|---|
| Max. Workpiece (OD x Module) | Φ350 mm x M8* |
| Max. Helix Angle | +/-45° |
| Table (C Axis) Diameter | Φ260 mm / Φ300 mm** |
| Spindle Nose Taper | BT#40 Taper |
| Max. Hob Size (OD x Length) | Φ150 mm x 220 mm |
| Max. Hob Shift Travel | 180 mm |
| Hob Spindle (B Axis) | Max. 1000 rpm | S1=35.8 Nm, S3=95.5 Nm |
| Table Rotation (C Axis) | Max. 200/300 rpm* | Direct-drive 900/1000 Nm* |
| Radial Feed (X Axis) | Max. 12000 mm/min | 250 mm (35-285 mm) |
| Tangential Feed (Y Axis) | Max. 2500 mm/min | 180 mm (0-180 mm) |
| Axial Feed (Z Axis) | Max. 10000 mm/min | 240 mm (150-400 mm) |
| Helix Angle Speed (A Axis) | Max. 720 deg/min | +/-45° |
| Hyd. Tailstock (U Axis) | Max. 6000 mm/min | 350 mm (340-690 mm) |
| Main Power | 35 KVA |
| Control System | FANUC 0i-MF Plus |
| Floor Space (L x W x H) | 3950 x 3450 x 2750 mm |
| Machine Weight | 10.0 ton |
* With automation OD max Φ260 mm ** Φ300 mm custom order
Standard Configuration & Optional Accessories
Standard Configuration
- C-axis direct-drive motor with backup rotary encoder
- Servo tailstock
- Mist cutting and machine-body cleaning device
- Tool pre-setter
- Post-cut spindle protection function
- Chip-scraper system
- Internal cooling device
- Mist centrifugal collector
- Hydraulic system
- Auto-lubrication device
- Pneumatic device
- Control cabinet with air conditioner
- Three-colour indicator light
- Mirror stainless chip-trough design
Optional Accessories
- Dry-cutting function
- End-face deburring device
- Second-cut device
- Servo tailstock upgrade
- Oil-mist electrostatic collector
- Dry-cut high-efficiency collector
- Magnetic contact detection
- Cutting fluid cooling system
- B-type new energy regenerative protection
- Large-diameter fixture and chuck
- Hobbing cutters M6-M8
- Rotary robot arm
- Auto loading/unloading system
- X-axis linear-guide force-clamping system
Customer Reviews & Case Studies
★★★★★
Australia — Mining Equipment MRO
We maintain a fleet of conveyor and crusher gearboxes at remote mine sites. The GBCTN-350 lets us produce M7-M8 replacement gears in-house, cutting our downtime-parts lead time from 12 weeks to under 3 weeks. The machine's ability to handle both disc-type and shaft-type workpieces without fixture changes is a genuine operational benefit.
— Workshop Manager, mining MRO facility
★★★★★
Czech Republic — Industrial Gearbox OEM
Our facility produces multi-stage helical reducers for the EU cement and aggregate sector. We machine Φ280-340 mm input gears in M6-M8 on the GBCTN-350. DIN Class 6 is achieved consistently without grinding — the direct-drive table eliminates the backlash errors that plagued our previous worm-table machine.
— Chief Production Engineer, industrial reducer plant
★★★★☆
Nigeria — Port Equipment Maintenance
We installed the GBCTN-350 to produce crane slewing-ring drive pinions and container-handler final-drive gears locally. The FANUC controller familiarity accelerated training. Remote diagnostic support from GBC resolved our initial coolant pressure alarm without a service visit — impressive for our location.
— Maintenance Director, port equipment overhaul workshop
Frequently Asked Questions
Q1: What is the difference between GBCTN-200 and GBCTN-350?
Both share the same machine-body platform. The GBCTN-350 features a larger C-axis table (Φ260/300 mm vs Φ200 mm), extended U-axis tailstock travel (350 mm vs 300 mm), and M8 module rating (vs M6), making it right for larger-diameter and coarser-pitch gear families. Machine weight is 10.0 ton vs 9.5 ton.
Q2: Can the GBCTN-350 produce internal (ring) gears?
The GBCTN-350 is configured for external gear and spline hobbing. Internal gear hobbing requires a shaping or broaching process. However, the GBCTN-350 can produce the mating external pinion and external features of ring-gear preforms in a single setup.
Q3: How is hob shift managed on long production runs?
The GBCTN-350 provides 180 mm total hob shift travel. The FANUC program supports automatic incremental shift at user-defined part count or flank-wear intervals, distributing wear evenly across the hob length and extending tool life by 40-60% compared to fixed-position hobbing.
Q4: What foundation preparation is required for the GBCTN-350?
A minimum 400 mm deep reinforced concrete foundation pad is recommended with four precision levelling bolts. Floor loading is 10.0 ton over the machine footprint. GBC supplies a detailed foundation drawing, anchor-bolt layout, and vibration-isolation specification with every order.
Q5: What export documentation and certifications are provided?
Every GBCTN-350 ships with a CE conformity declaration (EU markets), factory acceptance test (FAT) report with spindle accuracy and axis positioning data, packing list, and FANUC controller parameter backup disc. Third-party inspection by SGS or Bureau Veritas can be arranged on request.
Build Your Large-Module Gear Capability with GBC
Whether you are expanding an existing gear shop or establishing a new production line, the GBCTN-350 provides the rigidity, accuracy, and automation-readiness to compete in global markets. Reach out to discuss workpiece drawings, fixture requirements, and volume pricing.
View all models in the GBC CNC Hobbing Machine series or visit our homepage to learn about our full range of gear machining solutions.
The GBCTN-350 CNC 6 Axis Hobbing Machine processes large gear blanks up to Φ350 mm and module M8, delivering the high torque and rigidity demanded by heavy industrial, offshore, and energy-sector gear manufacturers. A Φ260-300 mm direct-drive table generating 900-1000 Nm torque and FANUC 0i-MF Plus control underpin its large-diameter ultra-precision machining capability.
